Polyaromatic compounds are of considerable interest because of their oxidative stability, thermal stability and, in some instances, their interesting electrical properties. Among the polyaromatic compounds, poly (phenylquinoline) and its derivatives are generally the most thermal oxidative stable polyaromatic polymers.
In U.S. Pat. No. 4,727,135 a polymer consisting essentially of recurring non-substituted polyquinoline moieties was reported. The non-substituted polyquinoline compound, as well as certain substituted polyquinoline compounds, was disclosed as being prepared by the catalytic dehydrogenative polymerization of tetrahydroquinoline and certain organo-substituted hydroquinoline derivatives.
Other heterocyclic containing polymers that have been investigated because of their potential utility in applications which demand high thermal and oxidative stability are the so-called polyquinoxalines and poly (phenylquinoxalines). (See Hergenrother, Paul M.,J. Macromol Sci.-Revs. Macromol. Chem., C6(1), 1 -28 (1971). These polymers are formed, for example, by the condensation reaction between bis (o-diamines), such as 3,3'- diaminobenzidine (1) with aromatic bis-glyoxals, such as p, p'-oxybis(phenyleneglyoxal hydrate) (2) as shown in Equation 1 ##STR1## and by the condensative reaction of an aromatic bis(o-diamine) and dibenzils, such as p, p'-oxydibenzil (3), such as shown in Equation 2 below: ##STR2##
Other variations have been recorded in the Hergenrother reference. In all instances, however, the repeating unit in the polymer does not consist solely of quinoxaline or substituted quinoxaline moieties but, instead, they consist of moieties including a quinoxaline unit linked to some other structural unit such as phenyl ether, and the like.